Abstract: A digital signal is non-linearly processed without generation of alias components by modelling the required non-linear operation by the best available quadratic function. A transformation circuit for implementing the quadratic function ax.sup.2 +bx may be used. As a result, only the second harmonic of each original frequency component of the digital signal is generated. Space for accommodating the original frequency components and the second harmonics can be made either by sampling frequency up-conversion in an interpolation up-converting circuit which doubles the sampling frequency, or by bandlimiting the original digital signal to a quarter of the original sampling frequency. In either case, the second harmonics occur below the Nyquist limit and no alias components are generated. A video signal color corrector makes use of both of the above techniques.

Abstract: In order to include a break slot in a broadcast video signal, the signal is first fed through a RAM recorder having a variable delay. Reading of the signal from the RAM recorder is controlled in such a manner that the delay produced by the RAM recorder is reduced from an accumulated value. After the delay has been reduced by a desired amount, reading out of the signal from the RAM recorder is inhibited until the delay has increased again to no more than the accumulated value, thereby to produce a break slot having a duration no more than the reduction of the delay produced by the RAM recorder.

Abstract: In a slow motion video generation apparatus; successive fields of an input video signal are stored in field stores, a spatial interpolator spatially interpolates between lines of a field selected from those stored in the field stores to produce a spatially interpolated video signal, a temporal filter carries out temporal interpolation between a pair of fields of the same interlace polarity selected from those stored in the field stores to produce a temporally filtered video signal, a combining device selectively receives the spatially and temporally interpolated video signals, and a movement indicator compares the fields stored in the field stores to detect whether or not there is local movement in the picture represented by the stored fields and controls the combining device so that the output signal is substantially wholly constituted by the temporally interpolated video signal in picture areas where substantially no movement is detected and is substantially wholly constituted by the spatially interpolated